1. Field of the Invention
The invention relates to a separation circuit for a DRAM, more particularly, to a separation circuit for a DRAM for isolating from the sense amplifier a parasitic capacitance which existed in a pair of bit lines positioned between a sense amplifier and a bit line charging voltage supply circuit when data is stored at a memory cell in the DRAM.
2. Information Disclosure Statement
Generally, in prior art separation circuit for a DRAM, MOSFETs are provided between the sense amplifier and the bit line charging voltage supply circuit, so that the MOSFETs turn "off" when data in the predetermined memory cell is read, and the MOSFETs turn "on" when data is written to the predetermined memory cell. In case that the data in the memory cell is read, the MOSFETs having a relatively high on-resistance value turn "off", so that there is no problem. However, where the data is written to the memory cell, there is a problem since the on-resistance value of the MOSFETs is not approximately equal to zero. In other words, when the data is written to the memory cell, the problem occurs in that the transfer characteristics of the data transferred to the memory cell is deteriorated, since the on-resistance value of the MOSFETs actually reaches up to the several Kilo Ohms (K.OMEGA.).
Therefore, it is an object of the present invention to solve the problems set forth above and to provide an improved separation circuit for a DRAM, having high transfer characteristic of the data transferred to the memory cell, when the data is written to the memory cell.
It is a further object of the present invention to provide a separation circuit which when reading and writing data to and from a memory cell, the transfer of such data to the memory cell can be accomplished very rapidly and without signal loss, to thereby increase the sensing ability of the sense amplifier.
The preceding objects should be construed as merely presenting a few of the more pertinent features and applications of the invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to both the summary of the invention and the detailed description, below, which describe the preferred embodiment in addition to the scope of the invention defined by the claims considered in conjunction with the accompanying drawings.